1. Field of the Invention
The present invention relates generally to handwriting data entry, and more particularly to methods and systems for facilitating data entry using a pen input device.
2. Description of the Related Art
Pen input devices have been provided in which the movement of a stylus across a detector is sensed by the detector and converted into alpha-numeric characters by handwriting recognition algorithms. Signals representing the alpha-numeric characters are then electronically stored in a computer document or database. In previous devices, the stylus contains either an active transmitter with associated battery, or a passive transmitter that includes a coil which is inductively coupled to remote transmitting circuitry. U.S. Pat. No. 5,608,390 is representative of the former genre of pen input devices, and U.S. Pat. No. 5,619,431 is representative of the latter genre of pen input devices.
It will be appreciated that in either type of existing pen input device, a special purpose stylus is required. This not only increases the cost of the devices, but the special purpose stylli are large and/or heavy compared to ordinary writing instruments. Consequently, the special purpose stylli typically are cumbersome. Further, special purpose stylli are not commonly available, making rapid replacement difficult.
A system incorporating electrostatic coupling of signals through a human body as a medium for short range communication, referred to as Personal Area Network (PAN), is discussed in U.S. Pat. No. 5,796,827, owned by the same assignee as the present invention and incorporated herein by reference. As disclosed in the above-mentioned patent, using the principles of PAN a small, lightweight transmitter automatically communicates information to a PAN receiver via an electrostatic field with which the person conducts. Owing to the principles underlying PAN communications, the PAN receivers are small, low power, low latency, low cost receivers that can be easily disposed on a variety of devices. The receivers sense signals that are sent by the transmitter and that are coupled to the person's body.
We have recognized that the principles of PAN electrostatic communication can be used to provide a pen input device that overcomes the above-noted drawbacks of existing pen input systems by permitting the use of an ordinary, off-the-shelf writing instrument. Thus, the present invention recognizes that it is possible to overcome the above-noted problems efficiently and effectively.